IEC 61850 substation gateway

ABSTRACT

An IEC 61850 Network Control Center (NCC) server is provided at a gateway intelligent electronic device (IED) of a Substation Automation (SA) system. The NCC server serves, via the MMS/TCP/IP part of IEC 61850, process data from substation Intelligent Electronic Devices IEDs to a NCC. The NCC server uses functional names for gateway Logical Nodes (LN) corresponding to substation LNs. The functional names are devoid of any reference to a substation IED related name of the substation LNs, but can be automatically translated to substation IED related names in case of changing SA communication and substation IED architecture. Thereby, functional names as defined by the substation section within a SCD file of the SA system are used for the communication link between the gateway IED and the NCC.

RELATED APPLICATION

This application claims priority under 35 U.S.C. § 119 to EuropeanPatent Application No. 11157128.7 filed in Europe on Jul. 3, 2011, theentire content of which is hereby incorporated by reference in itsentirety.

FIELD

The present disclosure relates to the field of Substation Automation(SA) systems for operating substations in high and medium voltage powernetworks, and more particularly, to communication connections between aSA system and a Network Control Center (NCC).

BACKGROUND INFORMATION

Substations in high and medium-voltage power networks include primarydevices such as electrical cables, lines, bus bars, switches, powertransformers and instrument transformers, which are generally arrangedin switch yards and/or bays. These primary devices are operated in anautomated way via a Substation Automation (SA) system. The SA systemincludes secondary devices, so-called Intelligent Electronic Devices(IED), which are responsible for protection, control and monitoring ofthe primary devices. The IEDs may be assigned to hierarchical levels,for example, the station level, the bay level, and the process level,the latter being separated from the bay level by a so-called processinterface. The station level of the SA system includes an Operator WorkStation (OWS) with a Human-Machine Interface (HMI) and a gateway to aNetwork Control Center (NCC).

A communication standard for communication between the secondary devicesof a substation has been introduced by the InternationalElectrotechnical Committee (IEC) as part of the standard IEC 61850entitled “Communication Networks and Systems In Substations”. Fornon-time critical messages, IEC 61850-8-1 specifies the ManufacturingMessage Specification (MMS, ISO/IEC 9506) protocol based on a reducedOpen Systems Interconnection (OSI) protocol stack with the TransmissionControl Protocol (TCP) and Internet Protocol (IP) in the transport andnetwork layer, respectively, and Ethernet as physical media.

SA systems based on IEC 61850 are configured and described by means of astandardized configuration representation or formal system descriptioncalled Substation Configuration Description (SCD). An SCD file includesthe logical data flow between the IEDs on the basis of message types ordata sets, for example, for every message source, a list of destinationor receiver IEDs, the message size in terms of data set definitions, aswell as the message sending rates for all periodic traffic. The SCD filelikewise includes the relationship between the IEDs as well as thefunctionality which the IEDs execute on behalf of the substation processor switch yard. SA systems with IEC 61850 have different architecturesand different ways of allocating functionality to Logical Devices (LD)or to physical devices (IEDs). The names of some IEDs are even dependenton the IED manufacturer and/or the IED purpose.

In order to interconnect IEC 61850 IEDs within the substation to an IEC61850 NCC, the TCP/IP based client server part of the IEDs and the NCCcan directly be used across any wide area network. However, this impliesseparate permanent TCP/IP connections to each individual IED inside theSA system and extensive resources and management at the NCC side, andmakes the NCC configuration highly dependent on the IED architecturewithin the substation. Furthermore, means for switching control accessbetween substation level and NCC level (e.g., between local and remote)must be implemented on all SA IEDs.

As an alternative, the use of a gateway from the SA side IEC 61850 busto the NCC side IEC 61850 protocol has been recommended. Such a gatewayoperates as an IEC 61850 client to all those IEDs supplying process data(such as primary equipment status, e.g. switch position, or primaryequipment supervision data e.g. gas alarms) intended for the NCC, and asan IEC 61850 server to the NCC for providing any process data changes ina configurable and controlled way via the MMS/TCP/IP part of IEC 61850.The gateway requires a configuration related to the SA system and itscommunication system on one side, and to the needed signals and signalqualities at the NCC on the other side. One simple method of configuringthe server side of the gateway is to instantiate proxy Logical Devices(LD) for all the LDs on the substation IEDs to the NCC side of thegateway. This leads to a simple gateway configuration and also testingprocess; however, it makes the NCC communication link dependent on theIED related naming and the physical as well as logical device structurewithin the substation.

On the other hand, for the NCC, a substation related functional viewbased on the primary substation single line layout and correspondingequipment and functions may be beneficial. Such functional structurechanges much less than the physical structure inside the secondary SAsystem, and might even to a large extent be known before the design ofthe SA system is finalized. Likewise, later extensions of the primarypart of the substation and the corresponding functionality might beknown long before the specific IEDs for the implementation have beendetermined.

In this context, the principles and methods of the present disclosureare by no means restricted to a use in substation automation, but arelikewise applicable to related process control systems with a formalsystem description. In particular, it has to be noted that IEC 61850 isalso an accepted standard for Hydro power plants, Wind power systems,and Distributed Energy Resources (DER). Further, it is also applicableto other protocols, as long as there is a formal description of thesignal meaning, like for IEC 60870-5-101/104 according to IEC61850-80-1.

SUMMARY

An exemplary embodiment of the present disclosure provides a gatewayintelligent electronic device (IED) for a Substation Automation (SA)system automating an electric power substation. The exemplary gatewayIED includes a communication interface configured to communicateaccording to IEC 61850, via a substation communication network, (i) witha substation Intelligent Electronic Device IED hosting a substationLogical Node (LN) instance with a substation IED related name, and, viaan Network Control Center (NCC) server of the gateway IED, (ii) with aNCC. The NCC server is configured to host a gateway LN instancecorresponding to the substation LN instance and has an NCC related nameindependent of the substation IED related name.

An exemplary embodiment of the present disclosure provides a method ofconfiguring a gateway intelligent electronic device (IED) forcommunication according to IEC 61850. The exemplary method includesconfiguring the gateway IED to communicate according to IEC 61850, via asubstation communication network of a Substation Automation (SA) system,with a substation Intelligent Electronic Device IED hosting a substationLogical Node LN instance with a substation IED related name. Theexemplary method also includes configuring the gateway IED tocommunicate according to IEC 61820, via an Network Control Center (NCC)server of the gateway IED, with a NCC. In addition, the exemplary methodincludes determining a functional name of the substation LN instancethat is independent of the substation IED related name, and configuringthe NCC server by instantiating a gateway LN instance corresponding tothe substation LN instance and having an NCC related name based on thefunctional name.

BRIEF DESCRIPTION OF THE DRAWINGS

Additional refinements, advantages and features of the presentdisclosure are described in more detail below with reference toexemplary embodiments illustrated in the drawings, in which:

FIG. 1 depicts a gateway interconnecting substation IEDs and a NetworkControl Center (NCC) according to an exemplary embodiment of the presentdisclosure;

FIG. 2 depicts the relation between functional and IED related names inIEC 61850, according to an exemplary embodiment of the presentdisclosure; and

FIG. 3 is an excerpt of an SCL file with a formal configurationdescription of a gateway, according to an exemplary embodiment of thepresent disclosure.

DETAILED DESCRIPTION

It is an objective of the disclosure to facilitate IEC 61850 basedcommunication between Intelligent Electronic Devices (IED) of aSubstation Automation (SA) system and a Network Control Centre (NCC).This objective is achieved by a gateway IED and a method of configuringa gateway IED according to the exemplary embodiments described below.

According to an exemplary embodiment of the present disclosure, an IEC61850 NCC server for serving, via the MMS/TCP/IP part of IEC 61850,process data from substation IEDs to the NCC is provided at a gatewayIED of the SA system. The NCC server uses functional names for gatewayLogical Nodes (LN) corresponding to substation LNs instantiated on thesubstation IEDs. With the exception of the generic LN class, thefunctional names are devoid of any reference to a substation IED relatedname as defined in IEC 61850-6, but can be automatically translated tosubstation IED related names in case of changing SA communication andsubstation IED architecture. In other words, functional names as definedby the substation section within a SCD file of the SA system are usedfor the communication link between the gateway IED and the NCC.

The proposed NCC server naming technique keeps the configuration of thesubstation function related data at the NCC-side of the gatewayindependent from the substation IED related structure or implementationinside the SA system. Hence, in case of changes or retrofit at the SAsystem, a reconfiguration of the SA-side of the gateway will besufficient. Furthermore, it will be possible to configure the IEC 61850communication link between the gateway IED and the NCC before the SAsystem as such is designed, and to commission this link independently ofthe commissioning of the SA system.

The present disclosure also relates to a non-transitorycomputer-readable recording medium (e.g., a non-volatile memory) havinga computer program including computer program code tangibly recordedthereon for controlling one or more processors of a) a gateway IED orother device adapted to be connected to a communication network of an SAsystem and configured to communicate with a substation IED and with aNCC, or b) of an IEC 61850 engineering tool of the NCC communicationsystem for generation of an IEC 61850 IID file of the gateway IED orother device, to carry out the features of the exemplary embodimentsdescribed herein. the

FIG. 1 depicts a Substation Automation (SA) system with three substationIntelligent Electronic Devices (substation IEDs) 10, 11, 12, and agateway IED 20 connected to a substation communication system or stationbus 15. The gateway IED 20 is communicatively connected to a NetworkControl Centre (NCC) 30. On a NCC-side or -end, the gateway IED 20includes an IEC 61850 NCC server 21 for conveying status signals,events, alarms, measurements and disturbance recordings from the SAsystem to the NCC. An exemplary substation Logical Node (LN) instance 13is hosted by substation IED 12, and a corresponding proxy LN instance 23resides on NCC server 21.

As noted by W. Wimmer in “Engineering a System of Systems”, paper 43presented at the PAC world conference 2010, Dublin, IE, the SubstationConfiguration Description (SCD) file of a SA system provides, in thesubstation section within the SCD file where LN instances are allocatedto the functional elements or pieces of primary equipment in thesubstation structure, for a translation between the LN instance names onthe substation IEDs and functional names that relate to theconfiguration or design of the substation.

FIG. 2 depicts such a correspondence between a functional name and asubstation IED related name for an exemplary substation LN instance. Thefunctional name AA1E1Q3QA1CSWI.Pos.stVal includes the substationdesignation (AA1), the voltage level (E1), the bay designation (Q3), theprimary equipment (e.g., switch) designation (QA1) as well as theLogical Node (LN) class (CSWI), LN data (Pos) and LN attribute (stVal).The corresponding substation IED related name Ctrl9LD1/Q0CSWI2.Pos.stValincludes the IED name (Ctrl9), the Logical Device (LD) name (LD1), theLN (CSWI) including LN prefix (Q0) and LN instance number (2).

In known techniques, an exemplary gateway or proxy LN instanceinstantiated on a gateway IED named “AA1Y1” and corresponding to theabove substation LN instance has a default NCC related name“AA1Y1LD1/Q0CSWI2” that retains a reference to the substation IEDrelated name via the LD instance identification “LD1”, the LN prefix“Q0” and the LN instance number “2”. In any case, and by means of thefunctional name (AA1E1Q3QA1CSWI), a SA-side SCD file (referencing thesubstation IED related name Ctrl9LD1/Q0CSWI2) can automatically betranslated into an NCC-side SCD file (referencing the NCC related nameAA1Y1LD1/Q0CSWI2), which ultimately supports automated engineering ofthe entire SA system. However, even if the engineering process as suchcan be automated, the communication link between the gateway and the NCChas to be newly configured and tested after any IED related changeinside the substation at the gateway as well as at the NCC side, becauseany such change is likely to impact the reference to a substation IEDrelated name of at least one gateway LN instance.

According to an exemplary embodiment of the present disclosure,functional names as defined by the substation section within a SCD fileof the SA system are used for the communication link between the gatewayIED and the NCC. Such functional name needs to be mapped, or cast, intoa proper format in order to become a valid NCC related name for an IEC61850 gateway LN instance. Hence, the functional name AA1E1Q3QA1CSWI ofthe above exemplary LN instance is mapped, for example, by the gatewayengineering tool for the NCC-side of the gateway IED, to the generic IEC61850 gateway IED related name parts, including gateway IED name, LDinstance ID (or alternatively the LD name, which per default is theconcatenation of the gateway IED name and the LD instance ID), LN prefixand LN instance number. The specific mapping to these parts has to beagreed on, and needs to respect the naming length restrictions of IEC61850 (Edition 2), for example, 64 characters for the LD name and 11characters for the LN prefix (with the LN instance number fixed to 1).

A simple way of assigning the functional name to the LD name and LNprefix at the NCC-side can include the following rules:

1. The name of the hierarchically lowest functional level (according tothe substation section of the SCD file of the SA system) to which an LNinstance is assigned or attached is used as the LN prefix.

2. The concatenation of all names of all the functional levels above thefunctional level to which the LN instance is assigned is used as LDinstance identification or as LD name, which in IEC 61850 edition 2 canbe defined independently from the IED name and the LD instanceidentification.

At present, seven functional levels (substation/voltagelevel/bay/function/subfunction/equipment/subequipment) are defined,implying that the name length at each level for an edition 2 gateway canamount to 64/7=9 characters. An exemplary length for the alphanumericpart of any IEC 81346 identification is 3 characters; in case of oneadditional sublevel 6 characters. This means that any typical IEC 81346functional naming scheme can be mapped in this way without any problem.In most cases, even an additional IED name (e.g. using the generatedname as LD instance ID instead of LD name) is no problem. In thiscontext, it is understood that all functional names are unique, forexample, at any functional level of the substation structure only oneinstance of a specific LN class is allowed.

In rule 2 above, using LD instance instead of LD name establishes theIED name as distinguishing identification element between differentsubstations, in case the substation names themselves are not uniqueagainst each other in the scope of the NCC.

In the example shown in FIG. 2, the LD related name part is AA1E1Q3, andthe LN prefix QA1 (the name of the functional level “function”). Withthe gateway IED named AA1Y1 the following two communication level (MMSdomain) NCC related name variants for the switch position are possible:

1. Mapping to IED name/LD instance: AA1Y1AA1E1Q3/QA1CSWI1

2. Mapping to LD name: AA1E1Q3/QA1CSWI1

If it is important to distinguish different gateways providing the samefunctional data items, the first method is recommended, which howevershortens the usable length for the SA function related name part.

FIG. 3 lists an excerpt of an IEC 61850 Instantiated IED Description(IID) file of a gateway according to an exemplary embodiment of thepresent disclosure. In detail, the two disconnectors “QB1” and “QB2”(bold-type emphasis added for the sake of legibility) in bay“Abgangsfeld Q3” of voltage level “E1” of substation “Musteranlage” areeach controlled via three LNs “XSWI”, “CSWI”, “CILO”. The correspondingproxy LNs on gateway IED “PROXYGW” have the LN prefix “QB1” and “QB2”,respectively, indicating the hierarchical functional level of the twodisconnectors, as well as the LD instance “MusteranlageE1Abgangsfeld Q3”

Using the above mapping mechanism implies that the NCC server names ofthe data may be already determined from the functional specification ofthe data to be provided on this link, the latter, for example, beingpart of the substation section of a System Specification Description(SSD) SCL file, where no IED specific name parts are used. A gateway IIDfile as in FIG. 3 for the NCC link describing the NCC serverconfiguration can be created from this SSD file, without any knowledgeabout the substation IEDs which will implement it.

Once the SA engineering is completed, the SA-side of the gateway will beconfigured from the complete SCD file, which includes the originalsubstation description from the SSD file and, in addition, thesubstation IEDs of the SA system, the links from the substation sectionto the LNs on the substation IEDs as well as the configured data flowfrom the substation IEDs to the gateway IED. A consistency check of theSCD file with the already existing gateway IID file can be done byverifying that all specified LN instances are actually assigned to asubstation IED. In case of inconsistencies, the gateway IID file can begenerated or completed from the SA SCD file, or specific NCC-sidequality attributes may be set to invalid. If any additional bays areadded, the gateway IED can first be reconfigured at the SA-side, stillallowing the NCC to access the ‘old’ part before the NCC-side isenhanced; or the NCC-side can first be reconfigured, providing theNCC-side configuration from the SSD file of the new bay before the SApart of this bay will be designed and commissioned.

Each substation LD residing on a substation IED includes a dedicatedLogical Node LN0 to commonly manage all LNs on this LD and also tomanage protection setting groups. On the other hand, there is no strictcorrespondence between function and IED oriented substation LDs and thegenerated LD structure on the gateway IED. Hence, the LD management atthe NCC-side is unrelated to any LD management in the SA system, inparticular and with a certain benefit to security concerns, settinggroup management cannot be handled from the NCC in a straightforwardmanner.

The basic functionality of a gateway to NCC is to provide access to thesubstation function related data, especially to the switch yard status,and to enable control of the latter by the NCC. Furthermore, the gatewaymay provide supervisory data about the substation IEDs of the SA system.The supervisory data may be provided by the L logical nodes on thesubstation IED, for example, LLN0 and LPHD as a minimum. Hence, a proxyimage of the substation IEDs might still be needed for this purpose, yetits contents can be restricted to one LD per physical substation IEDcontaining the needed L logical nodes. In particular, LLN0 and LPHD ofthe root logical devices, for example, allow for substation IEDsupervision as well as for the switching of protection setting groups ifneeded and secured by other means. The latter purpose could even be donevia the functional modelling of protection, if the LLN0 containing thesetting group control block is allocated to the appropriate protectionfunction in the SCL substation function structure.

In case that additionally engineering or asset management functionalityrequires remote access to the substation IEDs, the gateway could providea routing function with firewall and access control for direct access tothe concerned protection IEDs. Alternatively, asset management accesscould be provided via the functional view, at least for switch gear,thus also having the asset management model independent from the IEDsproviding the data. However, in this case, the needed values willprobably not be provided spontaneously by IEC 61850 reporting, as may bedone for the operational data, but instead (with exception of alarms tobe urgently handled, which may also go to the NCC) polled on demand bythe asset management system respective the asset manager. Thus, thegateway needs not just event based updating, but also transparent readrequests from the NCC side to the appropriate LNs at the SA side.

The method of a functional name related server structure to NCC can alsobe used, if the SA system is internally using another protocol than61850, for example, DNP 3 or IEC 101/104 resp. IEC 103. It is in thesecases especially advantageous if IEC 61850 SCL descriptions (ICD files)for the DNP/101/104/103 IED exist, as then standard IEC 61850 systemtools can be used to create the basic SCD file.

It will be appreciated by those skilled in the art that the presentinvention can be embodied in other specific forms without departing fromthe spirit or essential characteristics thereof. The presently disclosedembodiments are therefore considered in all respects to be illustrativeand not restricted. The scope of the invention is indicated by theappended claims rather than the foregoing description and all changesthat come within the meaning and range and equivalence thereof areintended to be embraced therein.

What is claimed is:
 1. A gateway intelligent electronic device (IED) fora Substation Automation (SA) system automating an electric powersubstation, the gateway IED comprising: a processor and memory; and acommunication interface of the gateway intelligent electronic device(IED) configured to communicate according to IEC 61850, via a substationcommunication network, (i) with a substation IED hosting a substationLogical Node (LN) instance with a substation IED related name, and, viaan Network Control Center (NCC) server of the gateway IED, (ii) with aNCC, wherein the NCC server is configured to host a gateway LN instancecorresponding to the substation LN instance and having an NCC relatedname based on a functional name that is devoid of any reference to thesubstation IED related name but automatically translatable into thesubstation IED related name in case of changing SA communication andsubstation IED architecture, wherein the functional name is retrievedfrom a substation section of a System Specification Description (SSD)file, the LN instances providing data objects relevant to NCCapplications are identified from the SSD file of the SA system, afunctional name for each identified LN is retrieved from the substationsection of the SSD file, and the NCC related name being independent ofthe substation IED related name.
 2. The gateway IED according to claim1, wherein the NCC related name of the gateway LN instance includes ahierarchically lowest functional level to which the substation LNinstance is assigned as an LN prefix of the NCC related name.
 3. Thegateway IED according to claim 1, wherein the gateway LN instanceincludes only data objects which are relevant to NCC applications. 4.The gateway IED according to claim 1, wherein the NCC server isconfigured to host a proxy IED instance corresponding to the substationIED, and includes a LN providing supervisory data of the substation IED.5. A method of configuring a gateway intelligent electronic device (IED)for communication according to IEC 61850, the method comprising:providing the gateway IED comprising a processor and memory; configuringthe gateway IED to communicate according to IEC 61850, via a substationcommunication network of a Substation Automation (SA) system, with asubstation Intelligent Electronic Device IED hosting a substationLogical Node LN instance with a substation IED related name; configuringthe gateway IED to communicate according to IEC 61850, via an NetworkControl Center (NCC) server of the gateway IED, with a NCC; determininga functional name of the substation LN instance that is based on afunctional name that is devoid of any reference to the substation IEDrelated name but automatically translatable into the substation IEDrelated name in case of changing SA communication and substation IEDarchitecture, and the NCC related name being independent of thesubstation IED related name; and configuring the NCC server byinstantiating a gateway LN instance corresponding to the substation LNinstance and having an NCC related name based on the functional name,wherein the determining the functional name comprises, retrieving from asubstation section of a System Specification Description (SSD) file ofthe SA system, a functional name for each identified LN, identifying,from the SSD file of the SA system, the LN instances providing dataobjects relevant to NCC applications, and retrieving, from thesubstation section of the SSD file, a functional name for eachidentified LN.
 6. The method according to claim 5, comprising:identifying a hierarchically lowest functional level to which thesubstation LN instance is assigned; and defining a LN prefix of the NCCrelated name of the gateway LN instance based thereupon.
 7. The methodaccording to claim 5, comprising: upon a change in the SA system,reconfiguring only an SA side of the gateway.
 8. A gateway intelligentelectronic device (IED) for a Substation Automation (SA) systemautomating an electric power substation, the gateway IED comprising: aprocessor and memory; and a communication interface of the gatewayintelligent electronic device (IED) to communicate according to IEC61850, via a substation communication network, (i) with a substation IEDhosting a substation Logical Node (LN) instance with a substation IEDrelated name, and, via an Network Control Center (NCC) server of thegateway IED, (ii) with a NCC, wherein the NCC server is configured tohost a gateway LN instance corresponding to the substation LN instanceand having an NCC related name determined from a functional name withoutany knowledge about the substation IED name, wherein the functional nameis automatically translatable into the substation IED related name incase of changing SA communication and substation IED architecture,wherein the NCC related name has no substation IED specific name parts,and wherein the functional name is retrieved from a substation sectionof a System Specification Description (SSD) file, the LN instancesproviding data objects relevant to NCC applications are identified fromthe SSD file of the SA system, a functional name for each identified LNis retrieved from the substation section of the SSD file, and the NCCrelated name being independent of the substation IED related name.